I’m wondering about this too. I’m on AT&T, and RCS was working all last week on my 15PM, and continued to work on Friday after moving to my 16PM. My girlfriend has a Galaxy S23 on Verizon and all texts up through Friday night were RCS, but Saturday morning suddenly only SMS worked. The text field shows RCS still, but anytime I text her it immediately fails, and the only way I can text her to to revert to SMS.
RCS does work for other people though. Was texting someone on T-Mobile a bunch this weekend and it was all RCS. Have also texted others on Verizon and AT&T and RCS works for those. So why would it suddenly not work just for 1 person? It keeps trying but always fails immediately.
I’ve toggled RCS multiple times, reset my network settings, tried on and off WiFi, etc.
Is this an AT&T issue, Verizon, Apple, or something with my phone? I’m not even sure where to go next.